Even if you don't check, other people should know that this is extremely misleading.
> Fewer clients, way more complex protocol
This is actually a valid complaint, though it's partly due to Matrix being pretty young. The other part is that Matrix does a lot more for you than IRC (eg e2ee and federation) and those extra features require complexity.
> The identity server is centralized
This is a completely optional part of Matrix. You don't need identity servers. You never have to provide your phone number. They don't even push you to when you sign up. It exists as a convenience feature for people who complain that they need to be able to discover their friends on Matrix by their friends‘ phone numbers. Also, you're free to run your own identity server for you and your friends or whomever.
> other attempts [at creating a homeserver] appear dead
This one is way off. Synapse, the "one complete server" you must be referring to, is going to be deprecated. The Matrix Foundation team is working on Dendrite to replace it. There are also several independent projects that are very active, notably Conduit, started by one guy unaffiliated with the Matrix Foundation team. Conduit is extremely far along and is under constant development.
> All of Matrix is controlled by New Vector LLC
The people who created Matrix were careful to separate their for-profit projects from FOSS community projects. Matthew Hodgson (Arathorn) explains it well here [0]. TLDR: The Matrix spec, the Element clients, and the Synapse/Dendrite homeservers are maintained by a nonprofit. Same team, different organization and funding. Everything is open source, so anyone is free to fork at any time.